In recent years, as a computer system becomes larger in scale, the use thereof is diversifying. A large-scale system has resources such as a plurality of system boards, a plurality of CPUs, a plurality of memories, and a plurality of HDDs (hard disk drives).
In addition to the use of such a large-scale system by operating a single virtual system using full resources, there is an increased use of a plurality of systems by dividing the large-scale system into a plurality of individual virtual systems, with necessary resources assigned to each.
To above systems which are independently operated, it is required to independently perform time management without being affected by other systems. Even when the single large-scale system is divided into the plurality of virtual systems, it is required to manage an operating time on the basis of each individual independent system.
However, each divided virtual system is no more than a system in which the resources of the large-scale system are assigned virtually, and it is not possible to mount time management hardware (clock timer) to each system. Therefore, it is required to incorporate a unit for managing the time of each individual virtual system, into a unit called a service processor (hereafter described as SP) for managing the large-scale system as a whole.
FIG. 8 is the conventional computer system configuration, FIG. 9 is an explanation diagram of the system time management thereof, and FIG. 10 is an explanation diagram of system time change processing. As shown in FIG. 8, the large-scale system includes N pieces of virtual systems 100-1-100-N, and a service processor 200. Each virtual system 100-1-100-N includes one or a plurality of CPUs 110, one or a plurality of memories 120, and I/O devices 130. A memory 120 stores OS (Operating System) 140 in an OS storage area 122, and also stores firmware 150 in a firmware storage area 124.
The OS 140 includes a firmware interface means (program), and the firmware 150 includes OS interface means (program), SP interface means (program) and time change information means (program).
The CPU 110 performs desired processing through the execution of the above OS 140 and firmware 150. The I/O device 130 is connected to the service processor 200, and includes a TOD 132, which plays the role of a clock timer, and an SP interface means (program) 134, as an example. The TOD 132 is constituted of an on volatile memory and a counter, and can retain a time even in case that the power is off.
The service processor 200 includes a TOD 202 which plays the role of a clock timer of the system, and an FW interface means (program) 204 having a time change information means.
In such a configuration, changing the time in the virtual system is carried out when executing an inspection test by performing some processing after setting the time to the past or to the future, and simulating a switch over of a computer, or the like.
Referring to FIGS. 9 and 10, the conventional time management method will be explained. First, the OS 140 provides a time change instruction to the firmware 150. The firmware 150 informs the TOD 132, which is time management hardware, of a set time (on the basis of a lapse of time) from the OS 140. The time management hardware 132 stores the above set time into a buffer area, and informs the service processor 200 of the change of time through the SP interface 134.
The service processor 200 acquires the instructed change time information from the buffer area of the time management hardware 132, and calculates a differential time with the change time based on a system time, by means of system time management hardware 202 of the overall system. The above differential time is written into the time management hardware 132 of the virtual system. On receipt thereof, the time management hardware 132 calculates the change time. Also, after writing, the service processor 200 informs the firmware 150 of the completion of time change setting, and the firmware 150 transfers the above information to the OS 140.
As such, conventionally, the service processor 200 calculates a differential time (New-time) between the time of the virtual system and a planned change time, sets the differential time into a memory area of the time management hardware 132 in the virtual system, and hardware calculates a time (for example, refer to Patent documents 1 and 2).
Patent document 1: The official gazette of the Japanese Unexamined Patent Publication No. Hei-11-015558.
Patent document 2: The official gazette of the Japanese Unexamined Patent Publication No. 2004-318878.